CaF₂ superstructures
(Result of the month 09/2007)

The recently delivered MCP-LEED to the University of Duisburg has already been producing results on complex insulating materials. In figure 1, the acquired LEED pattern was recorded using the Omicron MCP-LEED in a low beam energy mode at 49eV. The result shown is of the CaF₂ (3x1) superstructure on a Silicon (1x1) substrate. The CaF₂ insulating thin film was deposited (0.5 triple layer thick) at 355°C, after annealing to 760 °C.

Highlight: Spots that may be attributed to the original (1x1) structure onto which the CaF2 superstructure was grown.

Insulating CaF₂ superstructure on Si (1x1) measured using Omicron MCP-LEED

The MCP-LEED is capable of operating with very low beam current and this makes it ideal for work characterising thin film insulators such as CaF₂. The 6 bright spots of the outer ring can be attributed to the Silicon (1x1) pattern, whilst the inner spots are those of the CaF₂ superstructure.

Data Courtesy by: Prof. Hoern von Hoegen, University of Duisburg, Germany

This result has been obtained with :
MCP LEED

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